Machine for making dentures



l. NEUSTADTER 2,573,805

MACHINE FOR MAKING DENTURES 2 SHEETS- SHEET 1 INVENTOR BY ATTRNEY Nov. 6, 1951 Filed NOV. 16, 1949 Nov. 6. 1951 l. NEUsTAD'n-:R

MACHINE FOR MAKING DENTURES 2 sHEETs-sHEET-'z Filed NOV. 16, 1949 Patented Nov. 6, 1951 UN l TE D STAT S PATIENT OFF I CE MACHINE FOR MAKING DEN TURES Irving Neustadter, Brooklyn, N.Y.

Application November 16, 1949,-Serial No. 127,659

, 1 Claim.

The .object of vthis invention is ,to .provide a new and improved .machine for .making dentures. .The machine ,is .of .the .injector type such as is disclosed in my pending application led July 23, 1949, Serial Number 106,450. The invention embodied-.ina machine which includes a heat- .ingunit for receivingand plasticizing the plas- .tic granularrnaterial fromwhich fdentures are made. It also includes .mechanisms for ,injectin g .the `material intoa dental mold andis provided with certain -novelieatures and improvements .with respect to the injecting mechanism, `pressure Vcontrolling mea-ns and a Valve .for 4pre- Vventing,..pr.enfzat1.1re discharge of Athe plasticized .material .and .preventing ymaterial from -oozing out of the mold and back into the machine. .when the injection pressure is removed. Otherobjects `include means for generally improving the construction and appearance of the machine for more .eicient operation.

In thel accompanying drawings:

Fig. 1 .is a front view of `the machine with .a dental ilask .placed inposition to be filled Fig. .2 .is a central sectional View of Aparts of the heating unit and .shows a .mold in section about 'to .befllled with .denture material.

Fig. 3 is a View of the operating side of .the machine looking inthe directionof arrow 3 .in Fig. 1.

Fig. 4 isa face view of the pressure controlling means or torque relief mechanism.

Fig. 5 is a sectional view on the line .5-5 `of Fig. 4.

The machine has a base YII) adapted `to be mounted upon a table or bench. The base supports two upright .rods II, II which carry .two xed plates I2 and I3. The latter supportsa dental Mmaterial receiving and heating unit which is fenclosed within a casing I4. The unit has a feed Atube I5 open at the top in the plate I3. .At the bottom, Fig. 2, the tube carries a nozzle I6 and a material dividingplug II having grooved channels-I8. The tube is surrounded by an electrical heating elementZI), shown conventionally, within the casing I4. The nozzle I6 has a cone shaped outlet 2-I with an aperturel22. The nozzle carries a valve 23 with an opening 24 in alinement with the nozzle opening 22. Theyalveextends across the nozzle and has an operating handle 25, Fig.`3.

'Granular plastic material is poured .into :the feed tube'I-5 through'a-funnel 21mounted on the plate I3. The material is injectedinto the dental mold Yby a plunger'28 which moves within .the tube '15. The plunger, Fig. 3, is .provided with a rack3ll in mesh with an actuating gear 3l on an operating-shaft 32 :supported in bearings 33 on the plate I2.

.-At'the bottom of the machine .thereis a v ertically :movable flask carrying rplatform .35. `'supported ,on the. threaded shaft 36. The platform slides verticallyon the rods I I, see Fig. 2. A nut `3 is mounted on the .base I0 in threaded engagement with .the shaft. When the nut is rotated right or left, 4the platform 35 is raised or lowered asthecase may be.

The machine .is designed to operate with astandard dental ,-ilask as now generally used in .tlflelart` With this object vin View this invention includes aseparate `flask .holder unit. As seen in Figs. 1 .and .2 4the standard flask is marked 4i] andhas .the usual inlet.4;I in the top plate of the flask. By \.way of illustration there is shown in Fig. 2 va 4dental mold 42 which is to be lled to form a denture including teeth v43. The Ausual plaster .material is indicated at v44. The flask holder .unit consists. of a bottom- `plate 46 below ,theilask and a top plateli'l on Ytop'of the ask. .Whenthe lmold .has been prepared .the flask is vassembled in `known manner and Ithereafter the ila-sk .is clamped between the plates 46 and 41 by .bolts andlnuts 4 8. The vtopplateahas a conical inlet .53 -to .receive `the conical nozzle outlet 2l. ,In .order to controlv and regulate the injecting and compression pressure of the plunger 28 the following 4mechanism is provided. As seen in v1=.ir.fs...3-5the. operating shaft 32 has pinned there- .to afblockZ :by-aspin53. Surrounding ,the block .there is ra `cylindrical handle housing 54 which carries .fouroperating hand arms 55. The block `51 .and the housing 54 -are connected in driving flexible :operative yrelation Vby vtwo expansion springs f5.6. Set screws -as yat 58 Yare provided for adjusting .the voriginal spring pressure and for `assembling purposes. The housing 54 carries a .pointer and V a :scale fdisk 60 is secured to the -shaft.32 to 4turn therewith Aby means of `a screw -6.I. The disk carries 'a scale :62.

VIlheipurpose and function vof the special pressurecontrolling .and torque relief unit shown in Figs. 4 and 5 will best be understood in connecvtion .with ra .description of the `entire operation of :casting fa denture. Let it be assumed that the feeding 4tube I5 is -llled ywith plastic material .which-hasbeen melted by the heating unit which is usually-kept turnedon in the laboratory where adenture lis made. Let it -further be assumed that the dental mold has vbeenmade inthe flask maand the latter clamped in the holder. The yflask iunit 'is lthen .placed fupon `the platform 35 `andthe :latterlraised against the Anozzle 56 with .the-fconical lnozzle outlet 2| seated tightly inthe conical inlet '5,0 in the -top platel. Before the plastic material .is poured into the feeding `tube I 5 .the valve ,23 .isclosed so Yas to .prevent leakage of the melted plastic into the mold. Such leakage,in..the. formlofa .gob-or drop would quickly coolgbycontactwith.the ilask and harden to prematurely .clog the :inlets ..22 .and 4 I When Athe@.mieratar,is ready toiill themold he opens the valve 23 and takes hold of the arms 55 to rotate the operating shaft 32 to lower the plunger into the feed tube and force the plastic into the mold, the material flowing through the tube I5, down through the grooves 18 and the apertures 22 and 4I into the mold. When the mold is filled a resistance to further lling or movement of the plunger is felt by the operator in his hands as he turns the arms 55. He then observes the positions of the pointer 59 and the scale 6I which at this time indicate that the mold has been filled but not under compression pressure. During this feeding movement of the plunger the block 52 and the housing 54 have rotated together as if a single element. As the operator now continues to operate, a back pressure from the mold resists the rotating movement of the block 52. This resistance will be overcome in an increasing degree by the movement of housing 54 which Will compress the springs 56 and thus communicate the continued manual movement to the block 52 and the shaft 32.

The operator will know through experience and instruction how much further he has to turn the housing until the plunger has been lowered to such an extent that a predetermined compression pressure has been reached or exerted upon the material in the mold. Such predetermined compression pressure is noted by observing the pointer and the scale, and the operator therefore continues the rotating movement until these indicators inform him that the operation is completed. He then turns the arms backwards, to release the pressure upon th'e plunger and thereafter the springs 56 automatically restore the block 52 and the housing 54 to normal positions as shown in Fig. 4. The valve 23 is at all times operable independently of any other part of the machine, for example for cleaning the nozzle and the like.

As soon as the predetermined compression pressure is reached and before the plunger is raised from the mold, the valve 23 is closed to prevent the material from oozing up out of the mold and back into the nozzle and feed tube. The opening 50 in the flask holder will quickly be closed by the hardening of the material therein so after a few minutes wait the flask holder and iiask may be removed from the machine for final cooling and setting of the material, the platform being lowered for this purpose. Thus the operator need not wait for the cooling of the mold as would be the case were the fiask holder not provided. There will of course be as many flask holder units provided as the business requires.

In order to control and observe the orderly operation of the machine, the latter is provided with a thermometer 'I0 and a thermostat knob 15. The upper portion of the parts of the machine is enclosed by an ornamental housing 'I6 which has an opening in the top for the passage of the plunger. The housing nts over the plates I2 and I3, and has a slot as at 11, Fig. 3, so it can be lowered 4and raised over the shaft 32. The housing also carries a switch 18 and a light signal 19 in front. On the back there is the usual plug in terminal 80. The connecting wires are not shown. They are placed within the machine as may be most convenient and practical.

The operation of injection and compressing the plastic material within the mold is one continuous operation. The relative positions of the pointer 59 and the scale 6I are so designed and placed 4 that the commencement and finish of the compression movement are denitely indicated to the operator and the relief torque unit enables the operation to be carried out automatically with a calculated increase in pressure.

It will be seen from Figs. 1 and 3 that the machine is of novel pleasing design and construction. A11 the parts which must be observed during the operation are placed in front of the machine and ample space is provided for the placing and removal of the flask units. The valve 23 may extend in any direction from the nozzle as may be most convenient for reaching the handle. The mechanism for cushioning or gradually resisting the compression movement of the plunger is wholly enclosed. Only one pointer 59 is shown. There may be more than one. For example, four pointers may be used so that there will always be one pointer to be observed between two of the arms 55. The scale will then of course be extended to read in four quarter sections to match the pointers. Such additions or modifications are not illustrated, they being obvious multiplications of existing elements.

. There are no springs in the machine other than the springs 56 for gradually and automatically resisting and controlling the compression pressure and provide a cushion means therefor. It is an important feature of the invention that the machine operates with standard dental molds or asks.

I claim:

In a dental machine of the character described, a movable plunger for injecting melted denture material from said machine into a dental mold and for compressing said material in the mold to form a denture, said plunger, having an injection and a subsequent compression period of movement, mechanism for operating the plunger as aforesaid, said mechanism comprising an operating shaft, gearing means interposed between and operatively connected to said shaft and plunger for moving the latter when said shaft is rotated, a block member secured to the shaft, a housing enclosing said block member, springs interposed between the block member and the housing for yieldingly communicating a rotary movement of said housing to the block member, shaft and plunger, handles on the housing for rotating the same and means for automatically indicating the beginning of the compression period of the plunger during the rota.- tion of the said housing, said last mentioned automatic means consisting of a fixed dial and an indicator rotatably mounted thereon.

IRVING NEUSTADTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 133,229 Hyatt et al. Nov. 19, 1872 1,674,387 Campbell June 19, 1928 1,724,691 Andresen Aug. 13, 1929 2,035,801 Gastrow Mar. 31, 1936 2,279,952 Pryor Apr. 14, 1942 2,359,152 Pryor et al. Sept. 26, 1944 FOREIGN PATENTS Number Country Date 688,449 France May 12, 1930 350,810 Great Britain June 18, 1931 

